High-frequency circuit device having a circuit board fixed to a shield casing by projections of the shield casing and soldering

ABSTRACT

A high-frequency circuit device comprises a metal shield casing comprising side walls having projection parts projected innerwards and a plate-like member accommodated within the casing in contact with and fixed to the projection parts by dip-soldering. The plate-like member is either a printed circuit board having circuit elements mounted thereon or a shield plate segment for defining and shielding spaces above the printed circuit board.

This is a continuation of application Ser. No. 63,555 filed Aug. 3,1979, and now abandoned.

BACKGROUND OF THE INVENTION

This invention relates generally to high-frequency circuit devices, andmore particularly to a high-frequency circuit device in which aplate-like member such as a printed circuit board, a shield platestructure and the like are accommodated within and fixed to asquare-frame-formed casing. The plate-like member, making contact withan inwardly projecting part of the casing, is fixed to the casingthrough dip-soldering operation.

A typical example of a high-frequency circuit device is the electronictuning type tuner unit for UHF which has a printed circuit board havingshield plate segments projecting thereabove accommodated within a shieldcasing. Generally speaking, printed circuit boards of this type includesa number of circuits such as an antenna circuit, an RF circuit, a mixercircuit, an oscillator circuit, and an IF circuit, all of which areprovided with their circuit elements. A plurality of shield platesegments are mounted on the printed circuit board or assembled along theboundaries of the individual circuits to shield the circuits from eachother.

One example of a tuner unit known hitherto has adopted a mechanism forfixing a printed circuit board to a casing, in which mechanism theprinted circuit board is fitted inside the casing together with a shieldplate structure and is then fixed indirectly to the casing by solderingthe shield plate structure to the inside surface of the casing.Accordingly, this fixing structure involves disadvantages in that, thesetting or positioning of the printed circuit plate and the shield platestructure is apt to become unstable during the soldering work, thusdegrading precision. Moreover, as the soldering work is carried outmanually, the number of fabricating processes is large.

Furthermore, another example of a known tuner unit is of a constructionin which a printed circuit board is accommodated within a casing inengagement with a slit-and-bent part inside the casing and is solderedand fixed thereto. This conventional construction has the samedisadvantage as the construction just described, namely that thesoldering work is performed manually thus causing instability in thepositioning of the printed circuit board.

SUMMARY OF THE INVENTION

It is a general object of the present invention to provide a novel anduseful high-frequency circuit device in which the above describeddifficulties have been overcome.

Another and specific object of the invention is to provide ahigh-frequency circuit device in which a plurality of projection partsare formed in a shield casing on an inner side wall at its lower part,and a printed circuit board is brought into contact engagement with theprojection parts and is then fixed through dip soldering, whereby theprinted circuit board is accommodated within the casing. Here, theprinted circuit board is positioned at the lower part of the casing sidewall and is fixed through dip-soldering and this results in certainmerits which will be described later.

Still another object of the present invention is to provide ahigh-frequency circuit device in which L-shaped mounting lugs are formedby extending top ends of the opposing side plates or walls of a casing,and the casing is adapted to be mounted on a chassis, for example, byway of the mounting lugs. Because of the mounting lugs, the printedcircuit board can be subjected to dip-soldering operation with ease.

A further object of the present invention is to provide a high-frequencycircuit device in which a shield plate structure projecting above aprinted circuit board is accommodated within a casing in contactengagement near the top of the lateral end surfaces thereof with aplurality of internal projection parts which are formed on the shieldcase side walls at their upper parts, and is then subjected todip-soldering, thus fixing the shield plate structure to the casing andfurther the shield plate segments to each other. Adoption ofdip-soldering reduces the number of soldering processes and improves thestrength and precision of the solder joints.

Other objects and further features of the invention will be apparentfrom the following detailed description when read in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

In the drawings:

FIG. 1 is a perspective view showing a tuner unit as a first embodimentof the high-frequency circuit device according to the present invention;

FIG. 2 is a vertical sectional view taken along the line II--II in FIG.1 as viewed in the arrow direction;

FIG. 3 is a perspective view of an essential part of the tuner unit asviewed from the bottom thereof;

FIG. 4 is a fragmentary perspective view, from the bottom side, showingone embodiment of a mechanism for engaging a printed circuit board witha casing in the tuner unit;

FIG. 5 is a vertical section taken along the line V--V in FIG. 4;

FIG. 6 is a fragmentary perspective view, as viewed from the bottomside, showing another embodiment of the printed circuit board-casingengagement mechanism;

FIG. 7 is a vertical sectional view taken along the lines VII--VII inFIG. 6 as viewed in the arrow direction;

FIG. 8 is a fragmentary perspective view showing one embodiment of abottom casing cover of the tuner unit;

FIGS. 9 and 10 are perspective views respectively showing otherembodiments of the shield casing in the tuner unit;

FIGS. 11 and 12 are perspective views showing another embodiment of thetuner unit before and after being subjected to dip-soldering; and

FIGS. 13, 14, and 15 are fragmentary perspective views respectivelyshowing embodiments of the shield plate structure engagement structureof the tuner unit illustrated in FIG. 11.

DETAILED DESCRIPTION OF THE INVENTION

A description is first given of the structural arrangement of ahigh-frequency circuit device according to the present invention, inconjunction with FIG. 1 through FIG. 3.

Referring to FIG. 1, a UHF electronic tuning type tuner unit 10 includesa square-frame-formed tuner casing 11 which has four side walls 11athrough 11d. The side wall 11b is a separate member and is adapted to bemounted together with a printed circuit board 17 described hereinafter.The top parts of the opposing side walls 11a and 11c, which have noinput and output terminals mounted thereon, extend upwards and are bentinto L-shape, thus forming a pair of lugs 12 (12a and 12b) for mountingthe casing 11 in the apparatus in which it is to be used. Each mountinglug 12 comprises an extension part 13 and a mounting plate part 14. Eachextension part 13 is formed with a square opening 13a. The mountingplate part 14 of the mounting lug 12a has several holes 14a formedtherein, and the mounting plate part 14 of the mounting lug 12b hasseveral U-shaped cuts 14b. On the internal side of the extension part 13of the mounting lug 12b, are press formed a pair of projection parts13b.

The side walls 11a through 11d of the casing 11 have a plurality ofslit-and-bent parts 15 formed at specific positions on their lower edgesas indicated in FIG. 3 through FIG. 5 (in which the casing is shownupside down). The slit-and-bent parts 15 are formed by bending a partcut along an L-shaped groove at the lower edge of the casing walls.Furthermore, a pair of projection parts 16 are provided on each of sidewalls 11b and 11d at specific positions near the lower edges thereof.Each projection part 16 is formed by cutting two lateral and parallelslits in the side wall and inwardly deforming the part therebetween toform a bridge-like projection. These projection parts 16 are notessential, but they effectively serve to position the printed circuitboard 17 in the fixing operation.

The board 17 has circuit parts 18 and L-shaped terminals 19 mountedthereon with their terminal leads 18a and terminal parts 19a projectingbelow the board 17, and further has a shield plate segment 20 mountedthereon, as indicated in FIG. 1 through FIG. 3. This board 17 issubjected to a first dip-soldering operation before it is mounted in theshield casing 11 in FIG. 3, and the terminal leads 18a and the terminalparts 19a are thereby provisionally fixed to a specific conductorpattern 22a on the lower surface of the board in an electricallyconductive state. Thereafter, the terminal leads 18a projected below theboard 17 are cut substantially flush with the lower edge of the casing11, and the lead parts indicated by two-dot-chain lines in FIG. 3 areremoved. The projecting length l of the terminal leads 18a is thus madeas short as about 1 mm to 2 mm.

Following this, the board 17 is slidingly inserted into a U-shapedcasing 11 (to which no side wall 11b has yet been attached) from theopen side thereof. The direction of insertion is indicated by an arrow Ain FIGS. 1 and 2. During insertion, the board 17 is guided by theslit-and-bent parts 15 on the opposing side walls 11a and 11c. The board17 is then fitted to the casing 11 with its distal edge thereof engagedbetween the slit-and-bent parts 15 and the projection parts 16 on theleft side wall 11d in FIG. 2. Then, when the separate side wall 11b isfixed to the U-shaped casing, the proximal edge of the board 17 isbrought into engagement with and restricted betwen a set ofslit-and-bent parts 15 and projection parts 16 on the side wall 11b.This fabrication pricess may be modified in a manner such that the board17 and the side wall 11b are firstly fixed together to form a unitarysub-assembly structure, and the sub-assembly structure is then fitted tothe U-shaped casing 11. In either case, the board 17 is provisionallyfitted into the casing 11 engaged at its lateral edges between the fourprojection parts 16 on the side walls 11b and 11d and the plurality ofcut and bent parts 15 on the side walls 11a through 11d, and is thuspositively prevented from moving in the vertical direction.

Here, since only the opposing side walls 11d and 11b are provided withthe projection parts 16 which serve to restrict the free movement of theboard 17 in cooperation with the slit-and-bent parts 15, the fabricationprocess of installing the printed circuit board 17 can be carried outwith ease. It might be considered advantageous to us a structuralarrangement wherein the projection parts 16 are provided in the sidewalls 11a and 11c in addition to the side walls 11d and 11b since theprinted circuit board would then come into engagement at its fourlateral sides between the slit-and-bent parts and the projection parts.Engagement in this manner is, however, impossible in practicalapplication. Furthermore, in the case where the projection parts 16 arenot formed, the board 17 will be provisionally fitted so as not todisplace vertically by means of the shield plate segment (denoted by 20in FIGS. 11 and 12) described hereinafter.

When the board 17 is fitted as described above, each of the L-shapedterminals 19 projects side ways through a hole 11e formed in the sidewall 11b. The L-shaped terminals 19 thus projected are used forsupplying power, grounding, and checking the circuits for each frequencyband of the channel signals. An IF output terminal 23 is mounted on theside wall 11b and a VHF antenna input terminal 24 and a UHF antennainput terminal 25 are fixed to the sidewall 11d.

The L-shaped terminals 19 may be alternatively mounted on the board 17from the bottom thereof with the terminal part 19a thereof insertedthrough the board 17. In this structural arrangement, the terminal part19a at the lower part of the board 17 is fixed and electricallyconnected to a specific conductor pattern 22a by means of a mass ofsolder 21a formed by dip-soldering. The solder 21a also adheres to theterminal 19 itself but this does not give rise to any problems. In thecase where the terminal 19 projecting from the side wall 11b is to beconnected to another circuit, operation can be carried out more easilyif the terminal 19 is free from the solder 21a. Accordingly, when theterminal 19 is to be connected to a separate circuit, it is preferableto mount the terminal 19 from above the board 17.

Thereafter, the lower part of the casing 11 (board 17) is subjected tothe second dip-soldering operation. This dip-soldering operationelectrically connects the lead terminals 18a to the specific conductorpattern 22a. At the same time, each of the slit-and-bent parts 15 issoldered and electrically connected to the specific ground pattern 22bby a mass of solder 21b as indicated in FIGS. 3 and 4.

The pair of mounting plate parts 12a and 12b are formed above the casing11. Accordingly, the second dip-soldering operation can be easilycarried out with the casing held by the mounting plate parts 12a and12b. Moreover, the masses of solder 21b adhere to the inner and outerside surfaces of the casing 11 only at small areas near the lower edgeof the casing 11 and can therefore be easily covered by a fastening part32 of a bottom cover 31b. Thus the outside appearance of the device isnot impaired.

Furthermore, instead of the slit-and-bent part 15 in the above describedembodiment, it is possible to use a bent part 30 formed by bendinginnerwards a part defined between a pair of parallel slits extendingvertically from the lower edge of the casing 11, as indicated in FIGS. 6and 7. The board 17 is engaged between the bent parts 30 and theprojection parts 16, and the bent parts 30 are fixed and electricallyconnected to the ground pattern 22b by masses of solder 21b.

Comparing the constructions shown in FIG. 5 and FIG. 7, it will be notedthat the slit-and-bent part 15 shown in FIG. 5 facilitates the adherenceof a relatively large amount of solder 21b to obtain a solder joint ofideal shape which provides sufficient mechanical strength. Furthermore,in the case where the casing 11 is pre-coated with tin, for example, theconstruction indicated in FIG. 5 is more advantageous. This is because,in the slit-and-bent part 15 indicated in FIG. 5, a major part of thesolder 21b adheres to the pre-coated surface of the part 15 with goodadhesiveness, whereas in the slit-and-bent part 30 indicated in FIG. 7,a major part of the solder 21b adheres to the cut surface with pooradhesiveness.

Referring back to FIG. 2, a top cover 31a has an elastic fastening part32 formed around its periphery, and is attached to the top of the casing11 with the fastening part 32 pressing against the external side surfaceof the casing 11. The fastening part 32 confronting the lugs 12a and 12bpasses through the openings 13a and comes into pressing contact with theexternal side surface of the casing 11. Therefore, the fastening part 32of the cover 31a makes pressing contact with a substantial part of theperiphery of the casing 11. Consequently, the cover 31a is firmlyretained on the casing 11 in a play free state and, moreover, this coverhelps to improve the electric shielding characteristics of the casing.The position of attachment of the cover 31a is defined by cutouts incooperation with the pair of projection parts 13b.

The bottom cover 31b is of the same structure as the top cover member31a, except for slit-and-bent parts 33 which are additionally formed atspecific positions, as indicated in FIG. 8. This cover member 31b isattached to the bottom of the casing 11 by causing the fastening part 32to press against the side walls thereof, with the position of attachmentbeing determined by the contacting engagement of the slit-and-bent parts33 with the lower edge of the casing 11. Moreover, the cover surface 34makes pressing contact with elastic contact strips (not shown) providedat specific parts of the ground pattern 22b.

The fabrication of the tuner unit 10 is thus completed.

The completed tuner unit 10 is mounted on the chassis of the apparatusin which it is to be used (not shown) by screws (not shown) passingthrough the holes 14a and the cuts 14b in the mounting plate parts 14 ofthe pair of case mounting lugs 12a and 12b. Here, since the pair ofmounting lugs 12a and 12b are formed on the side walls 11c and 11d fromwhich no terminals project, the screw fastening work can be carried outwithout interference. Moreover, since one mounting plate part 14 isformed with cuts 14b, the work of positioning the tuner unit uponmounting can be carried out with ease, and furthermore, the work ofmounting and dismounting the device can be carried out very easily.

Furthermore, since the side walls 11a and 11c have no terminal holes oropenings which might decrease their mechanical strength, the mountinglugs 12a and 12b themselves serve as fastening members with largemechanical strength and with stable mounting structure. Therefore, theother side walls 11b and 11d of the casing 11 are subjected to almost nodeformation by the fastening force so that the terminals 19, and 23through 25 are not adversely affected by deformation.

In a modified fabrication process, the board 17 is provisionally fittedinto the casing 11 from its bottom opening and is engaged with theprojection parts 16 and the slit-and-bent parts 15 are then formed toclamp the board 17 in cooperation with the projection parts 16.

Moreover, in another modified fabrication process, the board 17 isfitted into the casing 11 with its circuit elements 18 through 20 merelyinserted therethrough. The assembled structure is then subjected todip-soldering one time and the lead terminals 18a are thereafter cut offto the desired projection length (approximately 1 mm to 2 mm). With thisfabrication process, dip-soldering need be performed one time. Thismodified fabrication process involving a single dip-soldering operationcan be reduced to practical application because the mounting lugs 12aand 12b do not interfere with the work of cutting the lead terminals18a.

A structure for provisionally clamping the board 17 may be modified suchthat the bridge-like projection parts 16 are disposed along the loweredge of the casing 11 and the slit-and-bent parts 15 are disposed near(but above) the lower edge of the casing 11. That is, in thisarrangement, the positions of the projection parts 16 and theslit-and-bent parts 15 are reversed from those of the presentembodiment. However, from the point of obtaining strong solderadherence, the present embodiment in which the slit-and-bent parts 15are positioned on the lower surface of the board 17 is moreadvantageous.

Instead of the pair of mounting lugs 12a and 12b, it is possible to usemounting lugs like those shown in FIG. 9. In FIG. 9, each of mountinglugs 35a and 35b has side cuts 36a formed one on either side of anextending part 36. These side cuts 36a serve the same purpose as theopenings 13a, that is to allow the fastening part 32 of the cover 31a topass therethrough. Moreover, mounting lugs 37a and 37b indicated in FIG.10 may be used. These mounting lugs 37a and 37b are respectively dividedinto three mounting lug segments 38a through 38c and 37a through 37cspaced at specific intervals. The fastening part 32 of the cover member31a passes through the space between the adjacent segments.

FIGS. 11 and 12 are perspective views showing other embodiments of thetuner unit in a state before and after being subjected to dip-soldering.In FIGS. 11 and 12, those parts which are the same as correspondingparts in FIGS. 1 and 2 are designated by like reference numerals, anddetailed description of such parts will be omitted.

The tuner unit 50 indicated in FIG. 11 is a semicompleted product which,upon conpletion, becomes the completed tuner unit 60 indicated in FIG.12. Side walls 11a through 11d of the casing 11 are provided withinternal projection parts 51 which are formed by embossing near the topof the casing so as to confront the side edge surfaces 20a through 20gof the shield plate structure 20 described hereinafter and are furtherprovided with pairs of projection beads 52 formed on the external sidesurface near the top and the bottom of the casing 11. The slit-and-bentparts 15 and the bridge-like projecting parts 16 in the embodimentindicated in FIG. 1 and FIG. 2 are not formed in the casing 11.

The shield plate structure 20 is pre-mounted on the printed circuitboard 17 so as to divide the electrical circuit into several circuitsections. The top of the shield plate structure is substantially thesame height throughout.

The sub-assembly comprised of the printed circuit board 17 and theshield plate structure 20 is inserted into the casing 11 from, forexample, the bottom opening thereof and the side edge surfaces 20athrough 20g of the shield plate structure 20 are elastically pressedagainst the respective projection parts 51. The force of friction atthis plurality of press-contact parts provisionally holds the printedcircuit board 17 in the casing 11. The pressed contact state between theside edge surface 20c of the shield plate structure 20 and theprojection part 51 of the casing 11 is shown in enlarged scale in FIG.13.

The printed circuit board 17 (shield plate structure 20) can beprovisionally held in position without any displacement within thecasing 11 even when the semicompleted tuner unit 50 is turned upsidedown.

The semicompleted tuner unit 50 is then turned over and is subjected todip-soldering, solder 53 thereby being adhered to the casing 11 asindicated by shaded portion in FIG. 12. The solder 53 adheres uniformlyover the top surface of the shield plate structure 20 and the sidesurfaces near the top surface, and the top surface and side surfacesnear the top surface of the casing 11, including the above described sixcontacting positions between the shield plate structure 20 and thecasing 11. Thus, the shield plate structure 20 and the casing 11, thatis the printed circuit board 17 and the casing 11, are securedpositively and regidly. The shield plate segments contacting each otherare also regidly fixed to each other near their tops.

Following this, the casing cover member 31a is attached to the casing 11so as to cover the top opening thereof, with the fastening part 32elastically engaging with the upper bead part 52. The bottom cover (notshown) is similarly attached to the casing 11. Thus the tuner unit 60 isnow completed.

The solder 53 adheres at either side (upper or lower) of the projectionbead 52 to form ramps which facilitate the attachment and detachment ofthe cover member 31a.

In the above described structural arrangement, the side edge surfaces20a through 20g of the shield plate structure 20 and the projection part51 of the casing 11 assume elastic contact with each other. Accordingly,when solder 53 adheres in the contact area, the members 20 and 11 aremore positively fixed and electrically connected to each other, thusimproving reliability to a higher level than is attainable in theconventional structural arrangement in which the side edge surfaces 20athrough 20g and the inside side surface of the casing 11 make onlyelastic contact and are thus susceptible to the formation of gapstherebetween. Moreover, since the solder 53 is applied throughdip-soldering, good solder adherence can be obtained and the timerequired for the soldering operation can be reduced to less than thatrequired in conventional soldering using a soldering iron. Furthermore,the soldering process can be carried out automatically.

Furthermore, since the solder 53 is fully applied over all contactingparts between the shield plate segments 20 adjacent to each other, andbetween the shield plate structure 20 and the casing 11, the contactresistance is effectively reduced. Small contact resistance, coupledwith no deviation in the set position of the shield plate structure 20,improves the Q-value of the circuit and prevents frequency deviation.Therefore, the tuner unit 60 exhibits stable tuning characteristics fora very long period of time.

FIG. 14 and FIG. 15 show other embodiments of the press-contactconstruction between the shield plate structure 20 and the casing 11.

Referring to FIG. 14, a bridge-like internal projection part 54 ispress-formed in the casing 11 and the shield plate structure 20 iselastically pressed at its side-edge surface 20c against the projectionpart 54 and is provisionally fixed.

Referring next to FIG. 15, instead of the internal projection 54indicated in FIG. 14, internal projecting lugs 55 are press-formed inthe casing 11. For example, the shield plate structure 20 is elasticallyclamped at its segments near the side edge surfaces 20a and 20b by meansof a pair of projecting lugs 55 on the side wall 11b of the casing 11and is thus provisionally retained.

Here, more stable provisional fixing can be obtained through astructural arrangement wherein, for example, the bottom surface of theboard 17 contacts with the slit-and-bent parts 15 at the lower edge ofthe casing 11 when the shield plate structure 20 is provisionally fixedby either the projection parts 51 and 54 or the projecting lugs 55 as inthe embodiments set forth above.

The circuit elements 18 and other circuit elements such as an antennacasing 56, all of which are at high positions near the top of the shieldplate structure 20 in FIG. 11, are apt to come in contact with themolten solder upon the above dip-soldering operation. Therefore, whenfound necessary, the electrical elements are coated with a heatresisting coating material to prevent damage from solder heating.

Even in the case where the shield plate structure 20 is fabricated fromplates pre-coated with metal plating, the side-edge surfaces 20through20g which are cut surfaces are susceptable to rust and erosion. However,as the solder 53 adheres to the side-edge surfaces 20a through 20g ofthe shield plate structure during the dip-soldering operation, rust andcorrosion are effectively prevented.

Moreover, when the cover member 31a is attached to the casing 11,slit-and-cut parts (not shown) press formed at specific positions on thecover member 31a come into contact with the top surfaces of the shieldplate structure 20 to constitute a part of the ground circuit. As thetop of the shield plate segment 20 is coated with solder 53, it ishighly resistant to rust. Therefore, the electric conductive state atthe contacting part is kept stable over a very long period of time.

The above dip-soldering operation can be carried out in the same mannereven in the case where bent parts are formed at the top edge of thecasing 11 or the shield plate structure 20.

In the tuner unit 60, the bottom surface of the board 17 is subjected todip-soldering operation once or twice, as in the case of the tuner units10 indicated in FIG. 1 and FIG. 2. Therefore, all soldering can becarried out by dip-soldering thus effectively reducing the amount oflabor required for soldering.

The high-frequency circuit device according to the present invention hasbeen described in respect of tuner units 10 and 60 which constitutetypical embodiments thereof. The present invention, however, is notlimited to such tuner units but may be applied to other various units ofa construction wherein a printed circuit board and a shield platestructure are accommodated or fitted inside a casing.

Further, this invention is not limited to these embodiments but variousvariations and modifications may be made without departing from thescope of the invention.

What is claimed is:
 1. A high-frequency circuit device comprising:ametal shield casing with surrounding side walls; a printed circuitboard-shield plate segment assembly supported horizontally within saidcasing, comprising a printed circuit board having electrical elementsthereon and shield plate segments which are perpendicular to saidprinted circuit board and define the electrical elements into aplurality of groups; holding means for provisionally holding saidassembly inside said casing so as to prevent displacement as betweensaid case and said assembly through mechanical contact between saidassembly and said casing; and solder parts for permanently fixing boththe top of said shield plate segments and the bottom of said printedcircuit board to said side walls of said casing by applying solder tocorresponding positions in a state where said assembly is provisionallyheld to said casing by means of said provisional holding means, saidprovisional holding means comprising projection parts formed on saidside walls of said casing, said projection parts bent from said sidewalls along a vertical axis and including vertex parts and said vertexparts of said projection parts making contact with the top of saidshield plate segments of said assembly, said solder parts between thetop of said shield plate segments and said projection parts beingdip-soldered parts.
 2. A high-frequency circuit device as claimed inclaim 1, wherein the solder parts between the top of said shield platesegments, the side walls of said casing, and between the bottom of saidprinted circuit board are dip-soldered parts.
 3. A high-frequencycircuit device as claimed in claim 1, wherein said provisional holdingmeans comprise projecting lugs formed on said side walls of said casingat positions confronting side edges of said shield plate segments, apair of projecting lugs being provided for each position so as to makecontact with the side edges of said shield plate segments, each of saidside walls of said casing having projections projecting outwards at anupper or lower part of the outer surface, said projections being coveredby a case cover so that soldered parts of the projections are covered bysaid case cover.
 4. A high-frequency circuit device comprising:a metalshield casing with surrounding front, rear, right, and left side walls;a printed circuit board having electrical elements thereon and shieldplate segments which are perpendicular to said printed circuit board;horizontal support means for holding said printed circuit board in astate where said printed circuit board is accommodated within saidcasing; and solder parts permanently contacting both said printedcircuit board and said shield plate segments and attaching them to saidcasing in a fixed manner by solder, said support means being projectionparts, at least one projection part being provided on each of at leastone pair of mutually confronting side walls of said casing andprojecting inwardly in a mutually confronting manner, said projectionparts bent from said side walls along a vertical axis, whileperpendicularly making contact with one surface of said printed circuitboard, and said solder parts of said printed circuit board which areheld by said projection parts being dip-soldered parts.
 5. Ahigh-frequency circuit device as claimed in claim 4, wherein saidprojection parts are bridge-like projections formed by cutting a pair oflateral slits in said side walls and inwardly deforming parts betweenthe slits.
 6. A high-frequency circuit device as claimed in claim 4,wherein said projection parts are slit-and-bent parts formed by inwardlybending parts cut along L-shaped grooves along an upper or lower edge orsaid side walls of said casing.
 7. A high-frequency circuit devicecomprising:a metal shield casing with surrounding front, rear, right,and left side walls, a horizontally supported printed circuit boardhaving electrical elements thereon, and shield plate segments which areperpendicular to said printed circuit board and which defines theelectrical elements into a plurality of groups; means for holding saidprinted circuit board so that said printed circuit board is accommodatedwithin said casing; and solder parts for permanently holding saidprinted circuit board and said shield plate segments to said casing bysolder, in the state where said printed circuit board is affixed saidaffixing means being projection parts, at least one projection partbeing provided on each of at least one part of mutually confronting sidewalls of said casing and projecting inwardly in a mutually confrontingmanner, said projection parts bent from said side walls along a verticalaxis, while perpendicularly making contact with one surface of saidprinted circuit board, with at least one of said solder parts beingdip-soldered parts.
 8. A high-frequency circuit device as claimed inclaim 7, wherein said projection parts are bridge-like projectionsformed by cutting a pair of lateral slits in said side walls andinwardly deforming parts between the slits.
 9. A high-frequency circuitdevice as claimed in claim 7, wherein said projection parts areslit-and-bent parts formed by inwardly bending parts cut along L-shapedgrooves at an upper or lower edge of said side walls of said casing. 10.A high-frequency circuit device comprising:a printed circuit boardcomprising electrical elements and shield plate segments which areperpendicular to said printed circuit board, said printed circuit boardbeing held within a metal shield casing by a pair of projection parts,bent from the side walls along a vertical axis, one of said projectionparts being a bridge-like projection formed by cutting a pair of lateralslits in a side wall of said casing and inwardly deforming parts betweenthe slits, the other of said projection parts being a slit-and-bent partformed by inwardly bending a part cut along an L-shaped groove at anupper or lower edge of said side wall of said casing; said printedcircuit board being inserted from a side opening of said casing whilepinched between said pair of projection parts, and thus fixed withinsaid casing; and both said printed circuit board and said shield platesegments being fixed by solder to said casing.